What is forward and backward chaining in Pega?


Staff member
Forward chaining is executed when the value of any of the source properties change.

Backward chaining mode executes when the target property is referenced somewhere.

Backward chaining is supported only for declare expressions.

In case of above expression: A=B+C

If B and C are changing frequently better to choose backward chaining. So that expression triggers only when A is used.


If A is used many places for display and calculations better to choose forward chaining. So that when input changes target is calculated and ready for usage.

Declarative Network: is nothing but a network in which output of one declare expression is input to the other for further calculations. It is designed for Forward Chaining and not useful for BC.